1st Diploma, Vienna University of Technology, 1997. Ph.D., Massachusetts Institute of Technology, 2003 (Gregory C. Fu). Postdoctoral: Massachusetts Institute of Technology, 2003-06 (Daniel G. Nocera). At Oregon since 2006.

Research Interests

Research in the Liu group focuses on the creation of novel molecules with interesting functions and properties. We will use the tools of organic and organometallic synthesis to assemble structures that address challenges ranging from anticancer therapy to multifunctional catalysis. We are also interested in the development of new synthetic methods. To this end, we will explore versatile rearrangement-based synthetic strategies that produce important targets in organic chemistry.

1) Our first research project seeks to open the interface between organic chemistry and boron neutron capture therapy (BNCT). BNCT has established itself as a very powerful binary form of radiation cancer therapy that can selectively destroy targeted cells containing a 10B nucleus. Despite promising clinical trials and significant achievements in the development of boron- containing BNCT agents, the big breakthrough of BNCT has been primarily hampered by the lack of available boron-containing drugs suitable for human clinical trials. We are developing strategies that will expedite the discovery of such therapeutics. The distinguishing feature of our approach to BNCT agent development is that the crucial boron atom is disguised as part of a stable structural motif that is isostructural and isoelectronic to the ubiquitous phenyl structure. We are currently developing novel boron-containing amino acids that mimic the properties of phenylalanine, tyrosine and tryptophan. These amino acids may be used directly as BNCT agents or they will serve as building blocks for more elaborate compounds possessing special functions and properties that assist in diagnosis and cellular targeting. A collaboration agreement has been established with members of the BNCT User Center at MIT. This center is the leading BNCT facility in the United States.

2) Our second research project seeks to develop new ligand frameworks that support multifunctional catalysis. Our catalyst design displays the following salient features: modular assembly, facile electronic fine-tuning, informative spectroscopic signatures, and a well-defined structure. In order to achieve these criteria, we will develop porphyrin-like macrocycles containing pyridine as the metal-coordinating fragment of the structure (Pymacs). The advantages of using pyridines for this function as opposed to pyrroles (in porphyrins) are that pyridines are readily functionalized and a variety of electronically diverse pyridines are commercially available. Thus, we will be able to use the spectroscopic signatures of Pymacs as a powerful mechanistic handle and at the same time fine-tune a metal’s electronic properties through substituents on pyridine. In the second stage of this program, we will incorporate Pymac adducts into spatially well-defined cofacial scaffolds through advanced cross-coupling technologies. The resulting multifunctional assemblies will be well suited for the discovery and optimization of novel catalytic reactivities including cooperative bimetallic catalysis and asymmetric synthesis.

3) The objective of our third research project is to discover and develop new atom-economic synthetic methods that rearrange readily available starting materials into more elaborate structures. Specifically, we will employ a transition metal-catalyzed transposition of allylic-type alcohols that productively repositions the hydroxy and the olefinic functionalities of a starting material for subsequent transformations. The simultaneous reshuffling of an olefinic and a hydroxy group can provide a straightforward entry point for tandem reactivity due to the versatile nature of both the olefin and the hydroxy functionalities. This general strategy can lead to a broad set of applications ranging from polyketide and polyol synthesis to carbohydrate and cross-coupling chemistry.

Publications:

"A Simple and Versatile Method for Alkene Epoxidation using Aqueous H2O2 and Manganese Salophen Catalysts." Liu, S.-Y.; Nocera, D. G. Tetrahedron Lett. 2006, 47, 1923-1926.

"Synthesis, Resolution, and Aldol Reactions of a Planar-Chiral Lewis Acid Complex." Liu, S.-Y.; Hills, I. D.; Fu, G. C. J. Am. Chem. Soc. 2005, 127, 15352-15353.

"Hangman Salophens." Liu, S.-Y.; Nocera, D. G. J. Am. Chem. Soc. 2005, 127, 5278-5279.

"The First General Method for the Synthesis of Transition Metal p Complexes of an Electronically Diverse Family of 1,2-Azaborolyls." Liu, S.-Y.; Hills, I. D.; Fu, G. C. Organometallics, 2002, 21, 4323-4325.

"1,2-Azaborolyls, Isoelectronic Analogues of the Ubiquitous Cyclopentadienyl Ligand: The First Synthesis of B-Heteroatom-Substituted 1,2-Azaborolyl Complexes and an
Assessment of their Electronic Features." Liu, S.-Y.; Lo, M. M.-C.; Fu, G. C. Angew. Chem. Int. Ed. 2002, 41, 174-176.

"A Surprisingly Mild and Versatile Method for Palladium-Catalyzed Suzuki Cross-Couplings of Aryl Chlorides in the Presence of a Triarylphosphine." Liu, S.-Y.; Choi, M. J.; Fu, G. C. Chem. Commun. 2001, 2408-2409.

"Simple Metal Alkoxides as Effective Catalysts for the Hetero-Aldol-Tishchenko Reaction." Mascarenhas, C. M.; Duffey, M. O.; Liu, S.-Y.; Morken, J. P. Org. Lett. 1999, 1, 1247-1249.

To Contact Dr. Liu:
lsy@uoregon.edu

WEBMASTER
lynde@uoregon.edu